Vapor generator wall and buckstay arrangement



Nov, 7, 1961 c. LIEB ETAL 3,007,455

VAPOR GENERATOR WALL AND BUCKS'I'AY ARRANGEMENT Filed Jan. 5, 1958 3Sheets-Sheet l FIGB INVENTORS Carl Lieb BY Russell L. Godshalk ATTORNEYNov. 7, 1961 c. LlEB ETAL 3,007,455

VAPOR GENERATOR WALL AND BUCKSTAY ARRANGEMENT Filed Jan. 5, 1958 I5Sheets-Sheet 2 00 2 i :TN 1 I o I 92 2 3 E3 2 il FIG.6

INVENTORS Carl Lieb BY Russell L. Godsnaik ATTORNEY Nov. 7, 1961 FiledJan. 3, 1958 c. LIES ET AI. 3,007,455

VAPOR GENERATOR WALL AND BUCKSTAY ARRANGEMENT 5 Sheets-Sheet 3 ATTORNEYnite States 3,097,455 VAPQR GENERATQR WALL AND BUCKSTAY ARRANGEMENT CarlLieb, Wadsworth, and Russell L. Godshalk, Akron,

Ohio, assigners to The Babcock & Wilcox Company,

New York, N.Y., a corporation of New Jersey Filed Jan. 3, 1958, Ser. No.706,922 13 Claims. (Cl. 122-6) This invention relates to a wallconstruction of a vapor generator and more particularly to an improvedtubular fluid cooled wall and b-uckstay construction suitable forforming the enclosure or chamber for containing the hot combustion gasesat various pressures ranging from below to above atmospheric.

in pressure operated vapor generators the walls defining the gas chamberthereof generally include a row of upright fluid cooled tubes reinforcedby laterally supported buckstay assemblies spaced at different elevationalong the upright portion of the wall forming tubes. As the row of tubesin the wall are in heat transfer relationship with tie combustion gasesand highly heated thereby for maintaining the temperature of the fluidflowing therethrough saturated while the buckstay assemblies in the wallare heated to only room temperature or slightly thereabove, the wall andbuckstays are thus subjected to relative rates of thermal linearexpansion during the expansionand contraction between the cold and hotposition thereof;

Heretofore, it has been customary to secure the buckstays to the vaporgenerator walls by means of pin and slot connections in order to providefor the relative thermal expansion of the walls and their respectivebuckstays. While the theoretical aspects of such pin and slotconstructions are satisfactory, it has been discovered that such a pinand slot construction is limited in its practical application from astrength standpoint whenever more than one pin is used. This is sobecause it is oftentimes impossible to have the load of the walldistributed equally on all the pins in excess of one in the thermallystressed position of the wall.

Other known wall and buckstay end connections while satisfactory eitherrequired excessive amounts of play or clearances between the partsthereof in order to accommodate the unequal expansion of the relativemoving parts or else require field fabrication to very close toleranceswhich tends to increase the cost thereof.

An object of the instant invention is to provide in a vapor generator animproved wall and buckstay arrangement wherein the load of the wall isuniformly distributed on the buckstay connection under all operatingconditions and which arrangement provides for a minimum amount of playor working tolerances between the parts thereof.

Another object is to provide an improved wall and buckstay cornerarrangement .in which the shop assembly of parts to the buckstay beamand/or wall tie bars is minimized.

Another object is to provide an improved wall and buckstay constructionwhich can be readily adapted simply and inexpensively to erectionconditions which may occur or prevail in the field on a particularinstallation and thereby facilitate the field erection of a vaporgenerator embodying the instant invention.

The above objects and advantages of the instant invention areaccomplished by connecting a buckstay to an upright Wall of a vaporgenerator by means of a link which has one of its ends pivotallyconnected to the wall and has the other end thereof pivotally connectedto the buckstay.

A featureof this arrangement resides in the provision of pre-setting ofthe opposite pivotal connections of the link in the cold position of thewall out of dead center position, the preferred out-of-center pre-setposition of the F is pivotal end connections being at least one half theexpected swing of the link so that relative expansion of the wall andbuckstay from its respective cold to its respective hot position willcause the link to move through its dead center position thus renderingthe relative position of the buckstay to the wall substantially the samein both the cold and hot position.

Other features and advantages will be readily apparent when consideredin view of the drawings and descriptions thereof:

FIG. 1 is a partial sectional plan view of a fluid cooled combustionchamber incorporating the novel buckstay con nection in accordance withthis invention.

H6. 2 is an enlarged detail plan view of the left hand corner viewed inFIG. 1.

FIG. 3 is a section view taken along line 33 of FIG. 1.

P16. 4 is a perspective view of the corner shown in FIG. 2.

FIG. 5 is a diagrammatic showing of the novel link connection in thecold, intermediate and hot positions thereof.

FIG. 6 is a partial sectional plan view of a fluid cooled chamberincorporating a modifie form of the buckstay end connection inaccordance with this invention.

FIG. 7 is a vertical end view taken along line '7-7 in FIG. 6.

FIG. 8 is a vertical section view taken along lined-8 in FIG 6.

FIG. 9 is a detail perspective view of the corner tie casting asutilized in the modified form of the invention.

The instant invention constitutes an improved Wall and buckstayarrangement as applied to a vapor generator wall construction of thetype disclosed in US. Patent No. 2,703,559 and the like.

As seen in FIGS. 1 to 4, the illustrated Wall construction includes aplurality of upright tubes lit arranged to define walls 11, 12 and 13 ofa furnace chamber 14 or the like for containing hot products ofcombustion gases, the inner I surface of the tubes being exposed in heattransfer relationship to the hot gases contained therein. As it iscustomary in vapor generators, the upper and lower ends of the tubes Itare appropriately connected into a fluid circulation system (not shown).Intermediate the vertical height of the tubes, which may be ofconsiderable extent in some installations, appropriately verticallyspaced, hori- Zontally extending tie bars 1'5, 16 and 17 secure thetubes in the respective walls in operative relationship to one another.As shown in FIG. 4, the tie bars of each wall are held in place by weldconnections 18, the juxtaposed end portions of the tie bars being weldedtogether at the corners. Thus in effect the tie bars form a band aroundthe periphery of the chamber. The outer area of the walls is thencovered with suitable casing and refractory or other insulating material(not shown). 1

In order to prevent any buckling of the tubular wall which may occurunder any abnormal operating condi-' tions, reinforcing buckstays 19, 20and 21 consisting of relatively large, horizontally disposed, I beamsare connected to respective walls 11, 12 and 13 at vertically spacedintervals of the walll As the buckstays 19, 20 and 21 are supported onthe walls exteriorally thereof, they are not subjected to the hightemperature of the wall tubes, and at best are only heated to roomtemperature or slightly thereabove. Consequently, in'opcration the walls11, 12 and 13 and their respective buckstays are subjected to relativeexpansion and contraction.

A' plurality of horizontally spaced clips or brackets 22 support eachbuckstay to its respective wall intermediate the ends thereof, thebuckstays terminating adjacent the marginal edges of their respectivewall. As seen in FIGS. 1 and 3, each bracket 22 consists "of a C-shapedplate 23 vertically disposed between mounting plate 24 and 25 by whichit is secured to the wall tubes with suitable weld connections. Eachbracket includes an upright portion 23A having laterally extending upperand lower portion 23B, 23C terminating with downwardly and upwardlyextending portions 23D and 23E respectively, to define a slot 26 in theshape of a T rotated 90". As shown, buckstays are supported on therespective walls by positioning the inner flanges thereof in thevertical slot 26 formed in the bracket. As will be hereinafter describedthe vertical slot 26 is formed sufliciently wide so as to provide for aslight outward movement of the buckstay I beam relative to the wall asthe wall and buckstay expand from cold to hot positions.

According to this invention the buckstays 19, 20 and 21 are connected tothe walls 11, 12 and 13 respectively for relative movement thereto bymeans of novel link connections in which the opposite end portions ofthe links are pivotally connected to the respective walls and buckstays.While the novel linkage construction may be equally adapted to a walland buckstay arrangement in which the relative linear expansion thereofoccurs in one direction only, by way of example, the description of theinstant invention will be directed to the wall 11 and its respectivebuckstay 19 in which relative expansion thereof occurs from its centerpoint outwardly in opposite directions.

Referring specifically to FIG. 1, each end of buckstay 19 has connectedthereto a plate 28 and 29 projecting beyond the ends thereof and towhich one end of links 30L and 30R respectively are pivotally connectedby pins 31L and 31R. The opposite ends of links 30L and 30R arepivotally connected to respective corner brackets 32 and 33 by pins 34Land 34R. As seen in FIG. 4, each link 30L and 30R may consist of a pairof members A and B disposed above and below the respective plates andcorner brackets and are connected thereto by common pivot pins 31L and34L. Buckstays 20 and 21 are likewise connected by similarly constructedlink means 35 and 36 to their respective walls 12 and 13.

In the cold position of the wall, as illustrated by FIG. 2, it will benoted that the center line of the pins of link connections arepreferably oflset. Thus in the cold position the perpendicular distanceL between the connecting pins of links is equal to distance between thepins centers times the sine of the angle A. Referring to FIG. 1 it willbe seen that as the wall 11 expands from its cold to the hot position,the movement of the corner will be in the general direction as indicatedby arrows E, the angular displacement being the resultant movement dueto the joint expansion of the adjacent walls 11 and 12 which form thecorner. Consequently as the walls will expand at a greater linear ratethan their respective buckstays, the links connecting the buckstays tothe walls will tend to move in an are so that angle A is increased, andas a result the perpendicular distances between the connecting pins ofthe links is increased. This increase in the perpendicular distances Lbetween the center lines of the connecting pins of the respective links,will cause the connected buckstays, which are movably mounted relativeto the respective walls, to be moved slightly outwardly relative to thewall an amount which is equal to the difference between the sines of theangle A in moving from the cold to hot position. The movement of thebuckstay 19 relative wall 11 is shown in FIGS. 3 as indicated by arrowsF. This slight movement of the buckstay relative to the wall duringexpansion will insure that the wall is free to expand at all timesrelative to the buckstay in a manner so as to avoid any possibility ofexcessively stressing the inner flanges of the buckstays and binding itto its supporting clip bracket 22, as for example flange 19A of buckstay19 on the edge 26A of slot 26 as shown in FIG. 3.

While the amount of the predetermined offset between the pivoting pinsof the links may be varied, in the preferred and illustrated form theoffset is equal to /2 the expected swing of the links as the wallexpands from the cold position to the hot position. Referring to FIG. 5,it will be seen that as the wall expands from its cold position A to itshot position C, the link 30, shown as a center line, will move throughan intermediate or neutral position B at which position the center linesof the pins are in alignment and angle A equals B. As the link movesfrom position A to position B angle A increases as do the perpendiculardistances L between the pins, the maximum perpendicular distance Loccurring when the center line of the pins are aligned in the neutralposition B. As the wall expands to its ultimate hot position as viewedin position C of FIG. 5, the link swings through its neutral positionand moves to the left thereof as shown. As the link moves to the left ofneutral, angle B decreases as do the perpendicular distances between thepins. Since the preferred setting of the links in the cold position issuch that the oflset position of the pins is /2 the expected swing ofthe link, angle A equals angle B and likewise the perpendiculardistances L1 is equal to L3 in the extreme positions of A and C. Thusthe relative position of the buckstay to the wall in the cold positionis the same as it is in the hot position.

FIGS. 6 to 9 are directed to a modified form of the invention. In thisembodiment the walls 111, 112, and 113 defining the furnace chamber 14or the like comprises a membrane welded wall structure, i.e. each wallincludes a row of spaced tubes in which a membrane forming member orweldment 110A connects adjacent tubes to form an imperforate wallsection. In this type of wall construction continuous tie bars welded tothe tubes, as in the hereinbefore disclosed loose tube wallconstruction, cannot be utilized. This is due to the fact that thediflerential expansion of the welded membrane wall versus a coldercontinuous tie bar would cause excessive compression stresses in themembrane or weldment.

The buckstay end connection in accordance with this invention thereforeincludes a corner tie casting 114 designed to distribute the buckstayend reaction loading over a sufiicient vertical length of membrane,which membrane is the only means for passing the load into the wallconstruction. As shown the corner tie casting 114 comprises a blockhaving inner arcuate defined face portions 114A, 114B for embracing thecorner tubes 115, 116 and the outer face portions 114C, 114D thereofshaped to define a squared corner. A weld secures the casting 114 tocorner tubes and 116. Accordingly, one or more corner castings 114 maybe superposed at the corner, depending on the vertical load distributionrequired on the membrane. To the casting or castings 114 is attached anangle plate 117 by means of bolts 118, the angle plate 117 havingoversized or slotted holes through which the bolts 118 project to permitvertical differential expansion between the walls and colder angleplate. Attached to the angle plate 117 by welding is a corner bracket orgusset 119 for taking the buckstay end connection linkage 120, which issimilar in all respects to that linkage connection hereinbeforedescribed.

A plurality of horizontally spaced clip-like brackets 121 support theintermediate portions of the buckstay 122 to the wall 111. According tothis form of the invention each bracket 121 includes a verticallydisposed channel member 123 having the toe portions 123A thereof weldedto two adjacent tubes. With this construction the channel member 123provides the desired flexibility to take the diflerential expansion ofthe wall 111 versus the colder channels 123 over the width of thechannels by flexing of the U-shaped channel contours. A verticallydisposed plate 124 is welded to the back of each channel and each plate124 has connected adjacent the upper and lower ends thereof an L-shapeprojection 125 and 125A to define a T-shaped slot 126, rotated 90.Received within the slot is the inner flange 122A of the buckstay 122.As hereinbefore described the slot 126 -is sufiiciently wide to providethe necessary clean ances to accommodate the movement of the buckstayrelative to the wall during the expansion and contraction thereof ashereinbefore described.

With the foregoing buckstay end constructions the load of the wall is atall times uniformly distributed since it will be transmitted to singlepin connections. Further, local structural conditions efiecting thepositioning of the buckstay end connection occurring during fielderection can be simply and easily compensated for by the properpositioning plates 23, 29 to the buckstay during erection for anyconditions which may occur. Further the novel link connection providesfor a minimum amount of play between the wall and buckstay and onceassembled no further adjustments are required.

While the instant invention has been disclosed with reference to aparticular embodiment thereof, it is to be appreciated that theinvention is not to be taken as limited to all of the details thereof asmodifications and variations thereof may be made without departing fromthe spirit or scope of the invention.

What is claimed is:

1. In a vapor generator with an upright wall having marginal edges and atransversely extending buckstay means to support said buckstay incontact therewith, said buckstay having its end portions terminatingadjacent the marginal edges of said well, and said wall and buckstaybeing subjected to relative transverse rates or" linear thermalexpansion between the extreme cold and hot positions thereof, theimprovement of connecting links securing the terminating end portions ofsaid buckstay to said wall, said links having their opposite endspivotally connected to said buckstay and said wall, said pivotal endconnections of said links being pro-set out of dead center in the coldposition of said wall and said buckstay to provide for movement of saidlinks through their dead center position in accommodating the relativetransverse linear thermal expansion of said wall and said buckstay.

2. In a vapor generator having two upright walls defining a cornertherebetween and a transversely extending buckstay and means to supportsaid buckstay in sliding contact therewith supported on each of saidwalls and spaced therefrom, said buckstays having juxtaposed endportions adjacent said corner, and said walls and the respectivebuckstay being subjected to relative thermal expansion in a directiontransversely of said wall between a hot and cold position; a cornerassembly for connecting the juxtaposed ends of said buckstays to therespective wall comprising a corner bracket connected to said walls, anda link for connecting the junxtaposed end of each of said buckstays tosaid bracket, the opposite ends of each of said links being pivotallyconnected to said bracket and respective buckstay, said pivotal endconnections of said links being pre-set out of its respective deadcenter position in the relative cold position of said walls andrespective buckstay and movable through its dead center position toresist the loads acting on said walls and to transmit said loads totheir respective buckstays.

3. A vapor generator comprising upright walls defining a cornertherebetween and each wall having a row of fluid heating tubes therein,a transversely extending tie bar in each of said walls rigidly connectedto the tubes thereof and terminating adjacent said corner, atransversely extending buckstay spaced from each of said walls, andmeans in sliding contact with said buckstay for supporting the same toits respective wall, said buckstays having terminating juxtaposed endportions adjacent said corner, a corner assembly connecting said tiebarsand buckstays including a corner bracket, a link connecting thejuxtaposed end portions of each buckstay to said bracket, said linkshaving their ends pivotally connected to said bracket and respectivebuckstay with the pivotal connections of each link being pre-set in thecold position out of dead center said links being movable through theirrespective dead center position upon relative movement between saidwalls and their respective buckstays in resisting a portion of the loadacting on said walls to maintain said corner tight throughout thermalexpansion and contraction thereof and to uniformly transmit said load onsaid walls to their respec tive buckstays.

4'. A vapor generator comprising upright walls adapted to thermallyexpand between a cold and hot position defining a corner therebetweenand each wall having a row of fluid heating tubes therein, a tie bar ineach of said walls rigidly connecting the successive tubes thereof andterminating adjacent said corner, a buckstay extending transversely ofsaid walls, each buckstay being sub jected to a relative rate of thermalexpansion of its respective wall, a clip member spacing the respectivebuckstays from each of said walls and supporting the same thereon, saidbuckstays being in contact with their respective clip members and havingterminating, juxtaposed end portions adjacent said corner, a cornerassembly connecting said tie-bars and respective buckstays including acorner bracket, a link connecting the juxtaposed end portionsof eachbuckstay to said bracket, said links having their ends pivotallyconnected to said bracket and respective buckstay with the pivotalconnections of each link being pre-set in the cold position of saidwalls and buckstay out of dead center to provide for movement of saidlinks through their dead centered position in accommodating relativelinear thermal expansion between the walls and their respective buckstaywhereby the latter is moved outwardly relative to its respective wall asthe respective links are moved through their dead center position.

5. In combination with two upright tubular membrane walls defining acorner junction therebetween, a buckstay for each well, support meansfor supporting each buckstay to its respective wall whereby saidbuckstays are in contact with said support means, and said walls andbuckstays are subjected to diiierential rates of thermal expansion andsaid buckstays having end portions adjacent said junction;theimprovement of corner tie casting connectedito the walls at thecorner junction thereof, link means, said link means having one endpivotally connected to the end portions of each buckstay and having itsother end pivotally connected to said corner casting, and flexing meansconnected to each of, said walls spacing the buckstay from each of saidwalls and supporting the same thereon.

6. In combination, an upright tubular membrane wall, a buckstay, saidwall and buckstay being subjected to differential rates of thermalexpansion, flexing means connected to said wall supporting said buckstayto said wall in spaced relationship thereto, and link means havingopposed end portions pivotally connected to the end portions of saidbuckstay and to said Wall to accommodate for said differential relativeexpansion.

7. In combination, an upright tubular membrane wall, a buckstay, saidwall and buckstay being subjected to differential rates of thermalexpansion, flexing means supporting said buckstay in spaced positionrelative to said wall, said flexing means including a channel memberhaving toe portions, said toe portions being connected to adjacent tubesof said wall, and an end assembly connecting said buckstay to said Wall,said assembly including a casting connected to said wall, a plateconnected to said casting so as to permit relative vertical expansiontherebetween, a gusset fixed to said plate, and a link pivotallyconnected to said buckstay and said gusset to accommodate relativethermal expansion between the wall and buckstay.

8. An upright wall means, a transversely extending buckstay in contactwith said wall means to resist the loading imposed on said Wall means,said wall means and buckstay being subjected to relative linear thermalexpansion, means for supporting and connecting said buckstay to saidwall means, said supporting and conmeeting means including a link meanspivotally connected at one end to the wall means and pivotally connectedat its other end to said buckstay to provide a connection therebetweento accommodate the relative transverse linear expansion occasionedbetween said wall means and said buckstay.

9. An upright wall means having a marginal edge portion, a transverselyextending buckstay in contact with said wall means for resisting theloading imposed on said wall means, said buckstay having an end portionterminating adjacent said marginal edge portion, said wall means andbuckstay being subjected to relative linear thermal expansion, means forsupporting and connecting said buckstay on said wall means, saidsupporting and connecting means including a link means pivotallyconnected at one end to the wall means and pivotally connected at itsother end to said buckstay to provide a connection to accommodate therelative transverse linear expansion occasioned between said wall andsaid buckstay.

10. A vapor generator comprising an upright wall having marginal edgeportions, a clip member connected to said wall intermediate the marginaledges thereof, a buckstay extending transversely of said wall, said clipmember supporting said buckstay on said wall in spaced relationshipthereto, said buckstay having its end portions terminating adjacent themarginal edges of said wall, said wall and said buckstay being subjectedto relative rates of linear thermal expansion between the extreme coldand hot positions thereof, connecting links securing the terminating endportions of said buckstay to said wall, said links having the oppositeends thereof pivotally connected to said buckstay and said wall, saidpivotal end connections of said links being preset out of dead center inthe cold position of said wall and said buckstay to provide for amovement of said link through its dead center position in accommodatingthe relative linear thermal expansion between said wall and saidbuckstay whereby said buckstay is moved slightly outwardly relative tosaid wall as the said links pass through the dead center position, saidoutward movement of the buckstay relative to said wall minimizing thestresses imposed by relative thermal expansion between said clip memberand said buckstay.

11. In combination with two upright wall means defining a cornertherebetween and a transversely extending buckstay on each of said wallmeans, means for supporting said buckstays in contact therewith on eachof said walls for resisting the loading imposed on the respective wallmeans, each of said wall means and its respective buckstay beingsubjected to relative thermal expansion, the improvement of a link meansconnecting each of said buckstays to its respective wall means, saidlink means having one end pivotally connected to a wall means and havingits other end pivotally connected to its respective buckstay to providea connection to accommodate relative thermal expansion between the wallmeans and their respective buckstays whereby said link means tend toresist the loading imposed on said wall means and maintain said cornertight during thermal expansion or contraction and to uniformallytransmit the loadings of said wall means to their respective buckstays.

12. In combination with two upright tubular membrane wall defining acorner junction therebetween, means for supporting a transverselyextending buckstay on each of said wall in sliding contact therewith,wherein said wall and buckstay are subjected to difierential rates ofthermal expansion and said buckstay having end portions adjacent to saidjunction; the improvement of a corner tie castings connected to the wallat the corner junction thereof, and link means having one end pivotallyconnected to the end portion of each buckstay and having its other endpivotally connected to said corner castings whereby said link meanstends to resist the load on said wall to maintain said corner tightduring differential expansion and to uniformly transmit the load actingon said wall to their respective buckstays.

13. In combination with two upright tubular membrane walls defining acorner junction therebetween, means supporting a transversely extendingbuckstay on each of said walls in sliding contact with said meanswherein said walls and buckstays are subjected to differential rates ofthermal expansion transversely of said walls, and said buckstays havingend portions adjacent to said junction; the improvement of a corner tiecastings connected to the walls at the corner junction thereof, an angleplate connected to said castings to permit relative vertical movementtherebetween, and link means having one end pivotally connected to theend portions of each buckstay and having its other end pivotallyconnected to said angle plate so that said walls move relative to saidbuckstays.

References Cited in the file of this patent UNITED STATES PATENTS1,627,043 Maudsley May 3, 1927 2,267,839 Rehm Dec. 30, 1941 2,655,238Langvand Oct. 13, 1953 2,700,375 Godshalk et a1. Jan. 25, 1955 2,773,487Walter et al Dec. 11, 1956 OTHER REFERENCES The Babcock & Wilcox Co.:SteamIts Generation and Use, published by Geo. McKibbon & Son, New York,U.S.A., 37th ed., 1955, pp. 20-7 and 20-14.

